{"id":160229,"date":"2024-11-03T21:21:21","date_gmt":"2024-11-03T13:21:21","guid":{"rendered":"https:\/\/server.hk\/cnblog\/160229\/"},"modified":"2024-11-03T21:21:22","modified_gmt":"2024-11-03T13:21:22","slug":"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-select","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/160229\/","title":{"rendered":"OceanBase \u6559\u7a0b\uff1aOceanBase SELECT"},"content":{"rendered":"<h1 id=\"oceanbase-%e6%95%99%e7%a8%8b%ef%bc%9aoceanbase-select-DwUBslqswM\">OceanBase \u6559\u7a0b\uff1aOceanBase SELECT<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u6578\u64da\u9a45\u52d5\u4e16\u754c\u4e2d\uff0c\u9078\u64c7\u5408\u9069\u7684\u6578\u64da\u5eab\u7cfb\u7d71\u5c0d\u65bc\u4f01\u696d\u7684\u6210\u529f\u81f3\u95dc\u91cd\u8981\u3002OceanBase \u4f5c\u70ba\u4e00\u6b3e\u9ad8\u6027\u80fd\u7684\u5206\u4f48\u5f0f\u6578\u64da\u5eab\uff0c\u5df2\u7d93\u5728\u591a\u500b\u884c\u696d\u4e2d\u5f97\u5230\u4e86\u5ee3\u6cdb\u61c9\u7528\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0e OceanBase \u7684 SELECT \u8a9e\u53e5\uff0c\u5e6b\u52a9\u8b80\u8005\u66f4\u597d\u5730\u7406\u89e3\u5982\u4f55\u5728 OceanBase \u4e2d\u9032\u884c\u6578\u64da\u67e5\u8a62\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%af-oceanbase%ef%bc%9f-DwUBslqswM\">\u4ec0\u9ebc\u662f OceanBase\uff1f<\/h2>\n<p>OceanBase \u662f\u7531\u963f\u91cc\u5df4\u5df4\u958b\u767c\u7684\u4e00\u6b3e\u5206\u4f48\u5f0f\u6578\u64da\u5eab\uff0c\u65e8\u5728\u63d0\u4f9b\u9ad8\u53ef\u7528\u6027\u3001\u9ad8\u64f4\u5c55\u6027\u548c\u9ad8\u6027\u80fd\u7684\u6578\u64da\u5b58\u5132\u89e3\u6c7a\u65b9\u6848\u3002\u5b83\u652f\u6301 SQL \u8a9e\u8a00\uff0c\u4e26\u4e14\u80fd\u5920\u8655\u7406\u5927\u898f\u6a21\u7684\u6578\u64da\u96c6\uff0c\u9069\u5408\u7528\u65bc\u91d1\u878d\u3001\u96fb\u5546\u7b49\u9700\u8981\u9ad8\u4e26\u767c\u7684\u5834\u666f\u3002<\/p>\n<h2 id=\"select-%e8%aa%9e%e5%8f%a5%e6%a6%82%e8%bf%b0-DwUBslqswM\">SELECT \u8a9e\u53e5\u6982\u8ff0<\/h2>\n<p>\u5728 SQL \u4e2d\uff0cSELECT \u8a9e\u53e5\u662f\u7528\u65bc\u67e5\u8a62\u6578\u64da\u7684\u57fa\u672c\u8a9e\u53e5\u3002OceanBase \u7684 SELECT \u8a9e\u53e5\u8207\u6a19\u6e96 SQL \u8a9e\u6cd5\u76f8\u4f3c\uff0c\u4f46\u4e5f\u6709\u4e00\u4e9b\u7279\u5b9a\u7684\u64f4\u5c55\u548c\u512a\u5316\u3002\u4ee5\u4e0b\u662f SELECT \u8a9e\u53e5\u7684\u4e00\u4e9b\u57fa\u672c\u7528\u6cd5\uff1a<\/p>\n<h3 id=\"%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-DwUBslqswM\">\u57fa\u672c\u8a9e\u6cd5<\/h3>\n<pre><code>SELECT [\u5217\u540d1, \u5217\u540d2, ...]\nFROM [\u8868\u540d]\nWHERE [\u689d\u4ef6]\nORDER BY [\u5217\u540d]\nLIMIT [\u6578\u91cf];<\/code><\/pre>\n<h3 id=\"%e7%a4%ba%e4%be%8b-DwUBslqswM\">\u793a\u4f8b<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba <code>users<\/code> \u7684\u8868\uff0c\u5305\u542b\u7528\u6236\u7684\u57fa\u672c\u4fe1\u606f\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5e38\u898b\u7684 SELECT \u8a9e\u53e5\u793a\u4f8b\uff1a<\/p>\n<h4 id=\"1-%e6%9f%a5%e8%a9%a2%e6%89%80%e6%9c%89%e7%94%a8%e6%88%b6-DwUBslqswM\">1. \u67e5\u8a62\u6240\u6709\u7528\u6236<\/h4>\n<pre><code>SELECT * FROM users;<\/code><\/pre>\n<h4 id=\"2-%e6%9f%a5%e8%a9%a2%e7%89%b9%e5%ae%9a%e5%88%97-DwUBslqswM\">2. \u67e5\u8a62\u7279\u5b9a\u5217<\/h4>\n<pre><code>SELECT username, email FROM users;<\/code><\/pre>\n<h4 id=\"3-%e4%bd%bf%e7%94%a8-where-%e6%a2%9d%e4%bb%b6%e9%81%8e%e6%bf%be%e6%95%b8%e6%93%9a-DwUBslqswM\">3. \u4f7f\u7528 WHERE \u689d\u4ef6\u904e\u6ffe\u6578\u64da<\/h4>\n<pre><code>SELECT * FROM users WHERE age &gt; 18;<\/code><\/pre>\n<h4 id=\"4-%e6%8e%92%e5%ba%8f%e6%9f%a5%e8%a9%a2%e7%b5%90%e6%9e%9c-DwUBslqswM\">4. \u6392\u5e8f\u67e5\u8a62\u7d50\u679c<\/h4>\n<pre><code>SELECT * FROM users ORDER BY created_at DESC;<\/code><\/pre>\n<h4 id=\"5-%e9%99%90%e5%88%b6%e6%9f%a5%e8%a9%a2%e7%b5%90%e6%9e%9c%e6%95%b8%e9%87%8f-DwUBslqswM\">5. \u9650\u5236\u67e5\u8a62\u7d50\u679c\u6578\u91cf<\/h4>\n<pre><code>SELECT * FROM users LIMIT 10;<\/code><\/pre>\n<h2 id=\"%e9%80%b2%e9%9a%8e%e7%94%a8%e6%b3%95-DwUBslqswM\">\u9032\u968e\u7528\u6cd5<\/h2>\n<p>\u9664\u4e86\u57fa\u672c\u7684\u67e5\u8a62\uff0cOceanBase \u9084\u652f\u6301\u4e00\u4e9b\u9032\u968e\u7684 SELECT \u8a9e\u53e5\u529f\u80fd\uff0c\u4f8b\u5982 JOIN\u3001GROUP BY \u548c\u5b50\u67e5\u8a62\u7b49\u3002<\/p>\n<h3 id=\"join-%e6%93%8d%e4%bd%9c-DwUBslqswM\">JOIN \u64cd\u4f5c<\/h3>\n<p>JOIN \u7528\u65bc\u5c07\u591a\u500b\u8868\u4e2d\u7684\u6578\u64da\u6839\u64da\u67d0\u4e9b\u689d\u4ef6\u9032\u884c\u806f\u63a5\u3002\u4ee5\u4e0b\u662f\u4e00\u500b\u7c21\u55ae\u7684 JOIN \u793a\u4f8b\uff1a<\/p>\n<pre><code>SELECT users.username, orders.amount\nFROM users\nJOIN orders ON users.id = orders.user_id;<\/code><\/pre>\n<h3 id=\"group-by-%e6%93%8d%e4%bd%9c-DwUBslqswM\">GROUP BY \u64cd\u4f5c<\/h3>\n<p>GROUP BY \u7528\u65bc\u5c07\u67e5\u8a62\u7d50\u679c\u6309\u67d0\u4e00\u5217\u9032\u884c\u5206\u7d44\uff0c\u4e26\u53ef\u4ee5\u4f7f\u7528\u805a\u5408\u51fd\u6578\u9032\u884c\u8a08\u7b97\uff1a<\/p>\n<pre><code>SELECT age, COUNT(*) as user_count\nFROM users\nGROUP BY age;<\/code><\/pre>\n<h3 id=\"%e5%ad%90%e6%9f%a5%e8%a9%a2-DwUBslqswM\">\u5b50\u67e5\u8a62<\/h3>\n<p>\u5b50\u67e5\u8a62\u662f\u6307\u5728\u4e00\u500b SELECT \u8a9e\u53e5\u4e2d\u5d4c\u5957\u53e6\u4e00\u500b SELECT \u8a9e\u53e5\uff1a<\/p>\n<pre><code>SELECT username\nFROM users\nWHERE id IN (SELECT user_id FROM orders WHERE amount &gt; 100);<\/code><\/pre>\n<h2 id=\"%e6%80%a7%e8%83%bd%e5%84%aa%e5%8c%96%e5%bb%ba%e8%ad%b0-DwUBslqswM\">\u6027\u80fd\u512a\u5316\u5efa\u8b70<\/h2>\n<p>\u5728\u4f7f\u7528 OceanBase \u9032\u884c\u67e5\u8a62\u6642\uff0c\u6027\u80fd\u512a\u5316\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5efa\u8b70\uff1a<\/p>\n<ul>\n<li>\u4f7f\u7528\u7d22\u5f15\uff1a\u70ba\u7d93\u5e38\u67e5\u8a62\u7684\u5217\u5efa\u7acb\u7d22\u5f15\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u67e5\u8a62\u6027\u80fd\u3002<\/li>\n<li>\u907f\u514d SELECT *\uff1a\u50c5\u9078\u64c7\u9700\u8981\u7684\u5217\uff0c\u6e1b\u5c11\u6578\u64da\u50b3\u8f38\u91cf\u3002<\/li>\n<li>\u5408\u7406\u4f7f\u7528 LIMIT\uff1a\u5728\u67e5\u8a62\u5927\u91cf\u6578\u64da\u6642\uff0c\u4f7f\u7528 LIMIT \u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-DwUBslqswM\">\u7e3d\u7d50<\/h2>\n<p>OceanBase \u63d0\u4f9b\u4e86\u5f37\u5927\u7684 SELECT \u8a9e\u53e5\u529f\u80fd\uff0c\u80fd\u5920\u6eff\u8db3\u5404\u7a2e\u6578\u64da\u67e5\u8a62\u9700\u6c42\u3002\u901a\u904e\u638c\u63e1\u57fa\u672c\u8a9e\u6cd5\u548c\u9032\u968e\u7528\u6cd5\uff0c\u4f7f\u7528\u8005\u53ef\u4ee5\u9ad8\u6548\u5730\u5f9e OceanBase \u4e2d\u63d0\u53d6\u6240\u9700\u6578\u64da\u3002\u82e5\u60a8\u5c0d\u65bc\u5982\u4f55\u5728\u9999\u6e2f\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u4e0a\u90e8\u7f72 OceanBase \u6709\u8208\u8da3\uff0c\u6216\u60f3\u4e86\u89e3\u66f4\u591a\u95dc\u65bc <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u7684\u8cc7\u8a0a\uff0c\u6b61\u8fce\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u4ee5\u7372\u53d6\u66f4\u591a\u8a73\u7d30\u8cc7\u6599\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Learn how to use OceanBase SELECT statements effectively with our comprehensive tutorial, covering syntax, examples, and best practices.<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-160229","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160229","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=160229"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160229\/revisions"}],"predecessor-version":[{"id":160230,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/160229\/revisions\/160230"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=160229"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=160229"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=160229"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}